The scorching weather finally brought play to a halt on the fourth day of the Australian Open when the temperature topped 109 degrees, but not soon enough for some players who criticized officials for not stopping matches earlier.

The Extreme Heat Policy was enacted at Melbourne Park just before 2 p.m. Thursday, suspending matches on outer courts until the early evening and requiring closure of the retractable roofs at Rod Laver and Hi-Sense arenas before play could continue on the show courts.

It was the first time since 2009 that play had been halted due to heat.

For Maria Sharapova, playing at Rod Laver Arena, the call came too late. The rule dictates the roof can't be closed until the end of a set in progress, so she was forced to finish a grueling third set against Italian Karin Knapp under the sun.

"Everyone knows there is no tiebreaker in the third set (at the Australian Open), so once you start that set, you're going to be out there until you're done," she said after closing out the 3 1/2-hour match, 6-3, 4-6, 10-8.

Other players wilted in the heat. American Varvara Lepchenko received medical treatment during her match against 11th-seeded Romanian Simona Halep, lying flat on her back during a changeover as trainers rubbed iced on her body.

"At first I didn't understand what was going on but then my legs, my arms started to get heavier. I couldn't focus at one point and started feeling dizzier," she said.

She continued but won only one more game in a 4-6, 6-0, 6-1 defeat.

The heat wave began Tuesday when the temperature peaked at 108 degrees. The tournament referee did not halt play then because the Extreme Heat Policy also takes into account other factors, such as humidity and wind speed.

The distinction is lost on the players, who have grumbled all week about the conditions which some have described as inhumane and dangerous. On Tuesday, Canadian Frank Dancevic blacked out and hallucinated during his match, while China's Peng Shuai vomited and suffered cramps.

The heat hasn't just affected players - it's also kept fans away. Total attendance was just 49,860 on Wednesday, down from Monday's high of 63,595.

Relief is at least in sight. Friday will be another scorcher, with an expected high of 111 degrees, but Saturday it is expected to reach only 73 degrees.